Many integrated circuit (IC) chips (dies) are with lids that basically enclose the IC chip and often other chips mounted on a package substrate. During electronic testing, force is often applied to the top side of the packaged IC to hold a contact array on the bottom of the package substrate against a test fixture. Depending on the lid design, a package lid can distribute force applied to the topside of the packaged IC around the perimeter of the lid, which avoids force directly on the IC chip and also avoids bowing of the package substrate, which can result in some of the contacts not engaging with the test fixture. If substantial force is necessary to hold the contact array of a non-lidded packaged IC, a die crack or solder fracture might occur.
One approach to avoid die cracking and solder fractures has been to maintain multiple simultaneous forces against the IC die and package substrate during testing. Unfortunately, this complicates the test fixture, especially if other components, such as chip capacitors, are surface-mounted on the package substrate.
Techniques for testing lidless packaged ICs with contact arrays are desirable.